1. Field of the Invention
The present invention relates to an agent for the suppression or lowering of blood lipids as well as cholesterol and neutral fats which comprises, as an effective ingredient, an edible dietary fiber having a effect of suppressing or lowering blood lipids, as well as cholesterol and neutral fats.
2. Prior Art
An abundance of epidemiologic research has confirmed that high levels of blood lipids in humans raises the rate of incidence of atherosclerosis and ischemic heart disease. In addition, it is thought that very many dietary factors influence blood lipids, involving the quantitative and qualitative changes of almost all nutrients.
In recent years, the continued Westernization of the daily diet in this country has been accompanied by an increase in adult diseases, while much has been said about the importance of dietary fiber in the relationship between diet and epidemic diseases. Also, an immense amount of epidemiologic and experimental research regarding dietary fiber has proven that it is an important dietary ingredient with a strong influence on blood lipids.
However, in laboratory reports so far, the general explanation has been that, of the dietary fibers, water soluble dietary fibers such as pectin, guar gum, gum Arabic, konjak mannan, etc. have a normalizing effect on blood lipids, and particularly cholesterol, while water insoluble dietary fiber sources such as wood cellulose, wheat bran, soybean fiber, etc. have no such effect (Keisuke Tsuji: "Non-nutrients and organic functions," ed. by Akira Yoshida, Etsuro Sugimoto, Kouseikan, p. 36, 1987). Also, the exertion of the effects of these water soluble dietary fibers is due to their effect of promoting the excretion of cholesterol into the feces.
On the other hand, there are also numerous reports regarding the blood lipid-lowering effect of water insoluble dietary fibers as well, and we the present inventors have already provided a report regarding the effect of beet fiber that means dietary fiber made from sugar beet (Japan Journal of Nutrition and Food Academy, 42, 295, 1989; Japan Journal of Agricultural Chemistry Academy, 66, 88, 1992; Japanese Patent Application SHO 62-49991).
Thus, at the present time there is an inundation of reports relating to dietary fibers, some stating the presence and others stating the absence of blood lipid-regulating effects. This may be due to the fact that there is no agreement between methods of investigation and testing, and that the majority of reports until now are concerned with the case of using purified dietary fibers isolated from plants, and also that dietary fibers encompass many and varied substances, each with unique physical and chemical properties which are closely related to the type of physiological effect and action of the dietary fiber.
However, in actual daily life, dietary fiber is not isolated and purified, but is ingested as complexes of various dietary fibers, in the form of vegetables, fruit, beans, grains and seaplants. Furthermore, since these complexes are what is traditionally meant by dietary fiber, it is important to determine the relationship between them and each fiber for the total properties and their physiological effects, though this is considered a difficult thing to do.
The various dietary fiber sources have different origins, and therefore they would be expected to each have their unique nutritional physiological effects; however, based on the fact that they are composed of common dietary fiber ingredients, we the present inventors wondered if these or other plant-derived dietary fiber sources might also have common suppressing or lowering effects on blood lipids, cholesterol and neutral fats.